Ever since breaking the inflationary cycle that hammered average Americans in 1979, the Federal Reserve board generally has been lauded for its technocratic competence. In pursuing its dual mandate of limiting inflation and promoting full employment, the U.S. central bank typically lowers interest rates when the economy is slowing and raises rates if it is overheating or at risk of a spike in inflation.

Yes, the Fed has made some big mistakes — Chairman Alan Greenspan was widely criticized for not doing more to prevent the “asset bubbles” that devastated Wall Street and triggered the Great Recession in 2007. But the bold interventions of Greenspan’s successor, Ben Bernanke — pumping money into the economy through “quantitative easing” — stabilized and revived the U.S. economy.

Now the latest Fed chairman — Donald Trump’s appointee Jerome Powell — is facing sharp criticism from the president for continuing the policies of his predecessor, Janet Yellen, and slowly increasing the “federal funds rate.” That’s the interest rate banks charge each other for overnight loans, and it directly affects the interest rate that banks charge customers for loans. Powell thinks that the economy is healthy enough for interest rates to return to normal levels after being kept unusually low since 2006. This makes sense. Unusually low rates can lead to excessive risk taking and housing bubbles.

But the president has said it is “foolish” and “incredible” that the Fed appears likely to raise its base loan rate by 0.25 percent to 2.5 percent on Wednesday and blames the Fed for the 12 percent plunge in the Dow Jones Industrial Average since its peak in early October. Analysts, however, say the primary reasons for the drop are the signs the global economy is weakening and fear of the fallout of the unfolding trade war that Trump launched with China.

The president may trust his “gut” to know more about dealmaking and the economy than “anybody else’s brain.” But Powell works for the people, not the president. He should trust his colleagues and his own judgment in making interest-rate decisions.